842 FXUS63 KLSX 050917 AFDLSX Area Forecast Discussion National Weather Service Saint Louis MO 417 AM CDT Thu Jun 5 2025 .KEY MESSAGES... - Isolated severe storms are possible this afternoon over southeast Missouri and on Friday over southeast Missouri and southwest Illinois. Damaging winds will be possible with strongest storms. - Periods of showers and thunderstorms are expected to continue through the weekend. && .SHORT TERM... (Through Late Friday Afternoon) Issued at 415 AM CDT Thu Jun 5 2025 Showers and thunderstorms have pushed southeast of the CWA early this morning as a weak shortwave trough is beginning to move into the Ohio Valley. The latest surface analysis is showing the cold front now lies from SLO to FAM. The latest HREF is showing that the front will clear all but the farthest three counties by this afternoon, with the RAP/NAM showing MLCAPES around 1500 J/kg. Forecast soundings are showing little capping at UNO/CGI with weak shear suggesting the far southern CWA could see one or two isolated storms capable of producing damaging winds. In addition, I can`t rule out locally heavy rainfall with these same storms given that the PWATS will be around 1.6" with slow storm motions. There will be a lull in the showers and thunderstorms with the front to the south of the area this evening. We will see some increase (30-40% chance) in showers and thunderstorms across central and southeast Missouri as the low level jet kicks in late tonight. A better chance for showers and thunderstorms will come on Friday when an MCS will move out of the Plains and tracks eastward. It is not clear yet the exact track of the MCS (i.e. whether it will move into the CWA vs. farther south) and whether MCS will weaken before it makes it into the CWA or will the resulting remnant MCV causes additional thunderstorm development over the CWA. Either way, there is still enough forcing and instability tomorrow to support 60-80% PoPs tomorrow along and south of I-70, particularly during the late morning and afternoon hours. The latest SPC slight risk for tomorrow still looks reasonable given the aforementioned uncertainties, with the primary risk being damaging winds, with large hail and tornadoes also possible. Britt && .LONG TERM... (Friday Night through Wednesday) Issued at 415 AM CDT Thu Jun 5 2025 The pattern still looks active through the weekend with the LREF showing a pair of troughs moving across the area. 30-60% of the LREF members are showing precipitation on Saturday ahead of the deep trough. The LREF is showing some higher joint probabilities (30-60%) for severe weather on Saturday, but another potential MCS moving across the area on Friday night may limit the instability for redevelopment later in the day. Another trough moving across the area late in the weekend will bring another chance (20-30%) of showers and thunderstorms on Sunday. Drier weather is expected next week when a upper ridge will move into the Midwest. Britt && .AVIATION... (For the 06z TAFs through 06z Thursday Night) Issued at 1100 PM CDT Wed Jun 4 2025 IFR ceilings are expected to cover much of the region overnight, accompanied by additional scattered showers and patchy drizzle and fog that could lower visibilities at times. KUIN will likely remain at the northern edge of lower ceilings with flight conditions varying between MVFR and VFR. Gradual improvement in flight conditions is expected Thursday morning through the afternoon via scattering/lifting of lower ceilings. The quickest improvement will be at KUIN, followed by KCOU and KJEF with VFR flight conditions forecast by late afternoon. At St. Louis metro terminals, VFR flight conditions may not be achieved before the end of the TAF period. Pfahler && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX